The following relates generally to wireless communication, and more specifically to two-symbol TTI operation for ultra-low latency (low latency) communication.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Wireless multiple-access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is Long Term Evolution (LTE). LTE is designed to improve spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards. LTE may use OFDMA on the downlink (DL), single-carrier frequency division multiple access (SC-FDMA) on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology.
A base station and a UE in a system employing multiple-access technology may operate according to a low latency physical (PHY) layer timing structure. Low latency operations (for example, operations based on a reduced transmission time interval (TTI)) may provide for reduced delay between a transmission and a HARQ response, for example. A low latency timing structure may also be configured to operate in concert with other timing structures of a system. This overlaid or parallel operation may introduce certain scheduling issues to be accounted for by a UE and base station. Additionally, in some cases, low latency operation may benefit from or introduce different considerations for identifying and utilizing reference signal.